/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.filesystem.stream;

import org.apache.flink.core.fs.Path;
import org.apache.flink.runtime.state.StateInitializationContext;
import org.apache.flink.runtime.state.StateSnapshotContext;
import org.apache.flink.streaming.api.functions.sink.filesystem.StreamingFileSink;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.NavigableMap;
import java.util.Set;
import java.util.TreeMap;

/** Writer for emitting {@link PartitionCommitInfo} to downstream. */
public class StreamingFileWriter<IN> extends AbstractStreamingWriter<IN, PartitionCommitInfo> {

    private static final long serialVersionUID = 2L;

    private transient Set<String> currentNewPartitions;
    private transient TreeMap<Long, Set<String>> newPartitions;
    private transient Set<String> committablePartitions;

    public StreamingFileWriter(
            long bucketCheckInterval,
            StreamingFileSink.BucketsBuilder<
                            IN, String, ? extends StreamingFileSink.BucketsBuilder<IN, String, ?>>
                    bucketsBuilder) {
        super(bucketCheckInterval, bucketsBuilder);
    }

    @Override
    public void initializeState(StateInitializationContext context) throws Exception {
        currentNewPartitions = new HashSet<>();
        newPartitions = new TreeMap<>();
        committablePartitions = new HashSet<>();
        super.initializeState(context);
    }

    @Override
    protected void partitionCreated(String partition) {
        currentNewPartitions.add(partition);
    }

    @Override
    protected void partitionInactive(String partition) {
        committablePartitions.add(partition);
    }

    @Override
    protected void onPartFileOpened(String s, Path newPath) {}

    @Override
    public void snapshotState(StateSnapshotContext context) throws Exception {
        super.snapshotState(context);
        newPartitions.put(context.getCheckpointId(), new HashSet<>(currentNewPartitions));
        currentNewPartitions.clear();
    }

    @Override
    protected void commitUpToCheckpoint(long checkpointId) throws Exception {
        super.commitUpToCheckpoint(checkpointId);

        NavigableMap<Long, Set<String>> headPartitions =
                this.newPartitions.headMap(checkpointId, true);
        Set<String> partitions = new HashSet<>(committablePartitions);
        committablePartitions.clear();
        headPartitions.values().forEach(partitions::addAll);
        headPartitions.clear();

        output.collect(
                new StreamRecord<>(
                        new PartitionCommitInfo(
                                checkpointId,
                                getRuntimeContext().getIndexOfThisSubtask(),
                                getRuntimeContext().getNumberOfParallelSubtasks(),
                                new ArrayList<>(partitions))));
    }
}
